DirectionsIn heavy 4-quart saucepan, with wire whisk, beat eggs, sugar, and salt until blended.
Gradually stir in 1 quart milk and cook over low heat, stirring constantly, until custard thickens and coats the back of a spoon (temperature on thermometer should reach 1603F), about 25 minutes.
(Do not boil, or mixture will curdle).
Pour custard into large bowl; stir in remaining 1 quart milk, rum if using, vanilla, and 1 teaspoon nutmeg.
Cover and refrigerate until chilled, at least 3 hours or up to 1 day.
To serve, in small bowl, with mixer at medium speed, beat cream until soft peaks for.
With wire whisk, gently fold whipped cream into custard mixture.
Pour eggnog into chilled 5-quart punch bowl; sprinkle with nutmeg.